A torsion damper of the above kind, in the form of a double flywheel, is disclosed in the specifications of U.S. Pat. No. 5,105,681 and French published patent application No. FR 2 660 038A. In the first of those documents, the stop elements are rotatable with the radial plates after a clearance has been taken up, while in the second document, the French published specification, the stop elements are in the form of blocks secured by riveting to the radial plates. In this type of damper, the resilient members, which in practice are of considerable length, may become jammed or rub in contact with the spacing element when the engine is operating at high speeds, and this is detrimental to good vibration damping. It is for this reason that in the document FR 2 660 038A, a second series of springs is provided, with an intermediate, auxiliary damper plate. Although being satisfactory in use, this arrangement does have the disadvantage of being extravagant in space and complicating the construction of the damper plate.